Production of laccases by the white-rot fungus trametes pubescens for their potential application to synthetic dye treatment

Resumen

Approximately 10,000 different dyes and pigments are produced annually worldwide and used extensively in the dye and printing industries. This has resulted in the generation of large volumes of highly polluted wastewater. Apart from the aesthetic deterioration of the natural water bodies, dyes also cause harm to the flora and fauna in the natural environment. Therefore, wastewater containing dyes must be treated prior to their discharge into the environment.Different methods can be applied for the treatment of synthetic dyes from aqueous solutions, such as ozonation, coagulation, flocculation, reverse osmosis and adsorption. However, biological treatments are promising alternatives with different approaches going from the complete immobilization of microorganisms to the pure enzyme utilization. Among all enzymes, laccases are an interesting alternative for the dye degradation due to their low affinity and wide specificity for the substrates. Laccases are multicopper oxidases found in higher plant and microorganisms, like white-rot-fungi; and carry out one-electron oxidation of phenolic and related compounds, and reduce O2 to water. Thus, this work proposes different strategies based on the use of laccases for the discoloration of synthetic dyes from aqueous solutions. These strategies include studies in different fields to promote eco-friendly solutions for different assets of the whole process. These studies include: the selection of substrates for the production of laccase by the white-rot fungus Trametes pubescens, the possible reutilization of these substrates in the discoloration process, the optimization of the laccase production per culture, the scale up of the laccase production, the use of free and immobilized laccase in the discoloration of dyes and the use of different immobilization techniques to increase the reutilization of the immobilized laccase for the treatment of synthetic dyes.